using System;

public class Program

{

    public static void Main()

    {

        string s1 = "Hello!";

        string s2 = "Yo!";

        Console.WriteLine("s1 = {0}", s1);

        Console.WriteLine("s2 = {0}", s2);

        Console.WriteLine();

        // Test these strings for equality.

        Console.WriteLine("s1 == s2: {0}", s1 == s2);

        Console.WriteLine("s1 == Hello!: {0}", s1 == "Hello!");

        Console.WriteLine("s1 == HELLO!: {0}", s1 == "HELLO!");

        Console.WriteLine("s1 == hello!: {0}", s1 == "hello!");

        Console.WriteLine("s1.Equals(s2): {0}", s1.Equals(s2));

        Console.WriteLine("Yo.Equals(s2): {0}", "Yo!".Equals(s2));

        Console.WriteLine();

    }

}